GCN Circular 9623
Subject
GRB 090708, Swift-BAT refined analysis
Date
2009-07-08T14:26:44Z (15 years ago)
From
Hans Krimm at NASA-GSFC <hans.a.krimm@nasa.gov>
D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC),
E. E. Fenimore (LANL), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA),
C. B. Markwardt (GSFC/UMD), A. M. Parsons (GSFC), T. Sakamoto (GSFC/UMBC),
G. Sato (ISAS), M. Stamatikos (GSFC/ORAU), J. Tueller (GSFC),
T. N. Ukwatta (GWU) (i.e. the Swift-BAT team):
Using the data set from T-239 to T+963 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 090708 (trigger #356776)
(Krimm, et al., GCN Circ. 9621). The BAT ground-calculated position is
RA, Dec = 154.632, 26.616 deg which is
RA(J2000) = 10h 18m 31.7s
Dec(J2000) = +26d 36' 58.7"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 27%.
The main pulse began at T-2 sec, peaked at ~T+4 sec and decayed by
~T+16 sec. There is a hint of some low-level emission out to ~T+100 sec.
At T+160 sec, a pre-planned slew took the burst out of the BAT field of
view. T90 (15-350 keV) is 15.0 +- 3.9 sec (estimated error including
systematics).
The time-averaged spectrum from T-1.3 to T+17.7 sec is best fit by a
simple power-law model. The power law index of the time-averaged
spectrum is 1.78 +- 0.22. The fluence in the 15-150 keV band is
6.9 +- 1.0 x 10-7 erg/cm2. The 1-sec peak photon flux measured from
T+3.37 sec in the 15-150 keV band is 1.3 +- 0.3 ph/cm2/sec. All the
quoted errors are at the 90% confidence level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/356776/BA/